In order to simplify the position and to avoid giving Black any chances, KataGo decided to capture Black's single stone immediately with .

Black's block at is mandatory.
Later, White will connect at in response to Black's atari at . In order to realize her territorial gain in the lower left, White will later capture Black's tail with a move at (Capture Variation).
White's connection at cost her two liberties in the Main Semeai, so Black will connect at in response to White's atari at to the same effect.

Let's calculate the territorial impact of KataGo's new moves. Shown is the board position after White's tsuke of Yamada Shinji with , where Black later played the atari at . We assume that White will chose the Capture Variation, which is better for her now.
– White gains five points by destroying Black territory (, ).
– White captures one Black stone (), so gaining one point.
– Black prevents the capture of , so gaining two points.
In total, White gains four points, so

Black wins the Capture Variation by 1 point.

Note: The Semeai Variation is not affected; it still ends by 3 points for Black.

Black would like to tenuki and to take the large endgame point in the upper left with .

White has a "simple" local refutation (she captures Black's nakade with ), so -- for the moment -- we can neglect the problem that this tenuki loses a decisive move in the Main Semeai.

As usual, Black reduces White's group at the left to only one eye.
But White has the cut of and the throw-in at at her disposal. Even if Black captures with , ...

... he does not have an answer to the atari of White . Black and ...

... White are miai, so White lives at the left edge.
The right half of the board is White territory now, so Black loses by a very large margin.

Black here indirectly defends against White's push at , and also defends against White's endgame move at , but is a fatal mistake.

White continues with the Main Semeai and starts taking Black's liberties in the upper right with , after having prevented Michael Redmond's kikashi in the bamboo joint (Black ; gaining an additional liberty) with the peep at first.
Black will suffer from the Punishment Semeai, because he lost a decisive move by not taking a liberty of White's group at the left.
As a matter of course, White will not connect her marked stones in the lower left during this process.